How Did the North/south Orientation of the Americas Affect the Unfolding

How did the north/south orientation of the Americas affect the unfolding of the Agricultural Revolution in that part of the world?

A) Farmers in the Americas developed no grain crop that could sustain large populations.
B) The successful domestication of large mammals by people in the Americas made crop domestication less important.
C) Crops were slow to spread because they had to adapt to different climactic and vegetation zones.
D) Agricultural innovations developed first in Mesoamerica and then spread north and south.